Cardiac Output and Regional Flow in Health and Disease - Essay Example

                The cardiac system is the system that is composed of the heart and the blood going through and blood total amount of blood released from the cardiac system is the cardiac output.
The primary function of the heart is to regulate an adequate cardiac output. Under normal physiological conditions, cardiac output is maintained equal to the perfusion need of various tissues. There are a series of mechanisms involved in order to achieve such control. The cardiac output usually varies widely according to physiological or environmental factors.

                As much as Cardiac output is the product of heart rate and stroke volume is also expected that factors that affect either of the two components would in turn affect the cardiac output. The human cardiac output usually varies according to the differences in age, size, or sex of an individual. A change in posture and or in the environmental temperature can also play a significant role in the volume of the cardiac output. These variations have been measured using different techniques of measuring cardiac output. The measurements have been obtained from the methods. In a healthy young male, the average cardiac output is 5.6 liters per minute. The cardiac output in females is 10% lower than that of males where factors such as age and body size remain constant during the cardiac output measurement.

                The typical phenomenon that controls the regulation of cardiac output is the venous return, the myocardial contractility, and the total peripheral resistance.
Cardiac output is regulated by the rate of venous return. Under normal circumstances, normal physiological circumstances are the primary determinant of cardiac output. The mechanism of cardiac out follows the mechanism of the Frank-Sterling law of the heart. However, it should be noted under normal physiological circumstances there is a limit beyond which a pumping action of the heart does not increase contrary to the rise in the venous system. The permissive level of the heart action is approximated to be between 13-15 liters per minute. An increase in the permissive level of the heart pumping action under very normal physiological conditions occurs in autonomic stimulation of the heart.

                Finally, under pathological circumstances, the heart fails to cope with the rate of the venous return and the cardiac output might fall below 3 or as far below 2 liters per minute at rest.